U.S. patent number 9,322,560 [Application Number 13/630,888] was granted by the patent office on 2016-04-26 for combustor bulkhead assembly.
This patent grant is currently assigned to United Technologies Corporation. The grantee listed for this patent is UNITED TECHNOLOGIES CORPORATION. Invention is credited to Frank J. Cunha, Nurhak Erbas-Sen.
United States Patent |
9,322,560 |
Erbas-Sen , et al. |
April 26, 2016 |
Combustor bulkhead assembly
Abstract
A heat shield is disclosed. The heat shield may comprise a body
having a back surface and an opposite front surface, wherein an
opening in the body communicates through the front and back
surfaces. The heat shield may further comprise at least one radial
rail disposed on the back surface and extending radially outward
from the opening for directing cooling air flow.
Inventors: |
Erbas-Sen; Nurhak (Manchester,
CT), Cunha; Frank J. (Avon, CT) |
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED TECHNOLOGIES CORPORATION |
Farmington |
CT |
US |
|
|
Assignee: |
United Technologies Corporation
(Farmington, CT)
|
Family
ID: |
50383948 |
Appl.
No.: |
13/630,888 |
Filed: |
September 28, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140090402 A1 |
Apr 3, 2014 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R
3/10 (20130101); F23R 3/283 (20130101); F23R
3/16 (20130101); F23R 3/04 (20130101); F23R
3/002 (20130101); F23R 3/50 (20130101); F23R
2900/03044 (20130101); Y02T 50/60 (20130101); F23R
2900/03043 (20130101); F23R 2900/03045 (20130101); Y02T
50/675 (20130101); F23R 2900/03041 (20130101) |
Current International
Class: |
F23R
3/00 (20060101); F23R 3/50 (20060101); F23R
3/16 (20060101); F23R 3/04 (20060101); F23R
3/10 (20060101); F23R 3/28 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
International Search Report for International Application No.
PCT/US13/51319; Date of Mailing: Dec. 6, 2013. cited by applicant
.
Written Opinion for International Application No. PCT/US13/51319;
Date of Mailing: Dec. 6, 2013. cited by applicant.
|
Primary Examiner: Sung; Gerald L
Assistant Examiner: Walthour; Scott
Attorney, Agent or Firm: Cantor Colburn LLP
Claims
What is claimed is:
1. A heat shield for a combustor comprising: a body having first
and second side edges, an inner edge, an outer edge, a back surface
and a front surface opposite the back surface, wherein an opening
in the body communicates through the front and back surfaces; a
plurality of effusion holes extending from the back surface to the
front surface, the plurality of effusion holes providing discharge
of cooling air flow from the back surface to the front surface; and
a plurality of rails disposed on the back surface for orienting and
directing cooling air flow, the plurality of rails including a
first side rail disposed on the first side edge, a second side rail
disposed on the second side edge, a circular rail disposed about
the opening, first and second mid-rails extending from opposite
sides of the circular rail, the first mid-rail joining the circular
rail and the first side rail, and the second mid-rail joining the
circular rail and the second side rail, a radially inner rail
extending along the inner edge, the radially inner rail joining the
first side rail and the second side rail, a radially outer rail
extending along the outer edge, the radially outer rail joining the
first side rail and the second side rail, and at least one radial
rail extending outwardly from the circular rail.
2. The heat shield of claim 1, wherein the plurality of effusion
holes extend at an angle from the back surface to the front
surface.
3. The heat shield of claim 1, further comprising at least one
oblong-shaped rib disposed on the back surface.
4. The heat shield of claim 1, further comprising a plurality of
radial inner ribs disposed on the back surface near the inner
edge.
5. The heat shield of claim 1, further comprising a plurality of
radial outer ribs disposed on the back surface near the outer
edge.
6. The heat shield of claim 1, wherein the combustor has a
centerline, and wherein the mid-rail divides the body into a
radially outward half and a radially inward half with respect to
the centerline of the combustor.
7. The heat shield of claim 6, further comprising: a first set of
effusion holes disposed between the radially inner rail and a
plurality of radial inner ribs, the radially inner rail and the
plurality of radial inner ribs directing the cooling air flow to
the first set of effusion holes; and a second set of effusion holes
disposed between the radially outer rail and a plurality of radial
outer ribs, the radially outer rail and the plurality of radial
outer ribs directing the cooling air flow to the second set of
effusion holes.
8. The heat shield of claim 7, further comprising a third set of
effusion holes surrounding the circular rail, and wherein the
radially inner, radially outer, first side, second side, circular,
first mid-, second mid- and at least one radial rails and the
plurality of radial inner ribs and the plurality of radial outer
ribs direct the cooling air flow to the third set of effusion
holes.
9. The heat shield of claim 8, wherein the plurality of radial
inner ribs and the plurality of radial outer ribs generally extend
circumferentially with respect to the centerline of the combustor
and are laterally oriented in a staggered arrangement near the
inner and outer edges, respectively.
10. The heat shield of claim 8, wherein a staggered arrangement of
the plurality of radial inner ribs and the plurality of radial
outer ribs at least partially separates the inner and outer edges
from the rest of the body.
11. The heat shield of claim 1, further comprising a plurality of
pins on the back surface, the plurality of pins spatially arranged
in a diamond formation.
12. The heat shield of claim 1, further comprising a plurality of
pins on the back surface, the plurality of pins spatially arranged
in a chevron formation.
13. The heat shield of claim 1, further comprising a plurality of
raised trip strips on the back surface, the plurality of raised
trip strips configured to further direct cooling air flow on the
back surface.
14. The heat shield of claim 13, wherein the plurality of raised
trip strips are v-shaped.
15. A bulkhead assembly comprising: a heat shield mounted to and
spaced apart from a shell, the shell having a plurality of
impingement holes through which cooling air flow passes and
impinges on the heat shield, the heat shield having a body having
first and second side edges, an inner edge, an outer edge, a back
surface, and a front surface opposite the back surface, wherein an
opening in the body communicates through the front and back
surfaces, a circular rail disposed about the opening, first and
second side rails disposed on the first and second side edges,
first and second mid-rails extending from opposite sides of the
circular rail, the first mid-rail joining the circular rail and the
first side rail, and the second mid-rail joining the circular rail
and the second side rail, a plurality of radial rails disposed on
the back surface and extending radially outward from the circular
rail, the plurality of radial rails dividing the back surface of
the body into a plurality of compartments for directing the cooling
air flow, a radially inner rail extending along the inner edge, the
radially inner rail joining the first side rail and the second side
rail, a radially outer rail extending along the outer edge, the
radially outer rail joining the first side rail and the second side
rail, and a plurality of effusion holes in the body communicating
through the front and back surfaces, the plurality of effusion
holes providing discharge of the cooling air flow from the back
surface to the front surface, wherein the first and second side
rails, the radially inner rail, and the radially outer rail orient
the cooling air flow toward the plurality of effusion holes.
16. The bulkhead assembly of claim 15, wherein each of the
impingement holes through the shell is located to achieve
isothermal temperatures on the heat shield.
17. The bulkhead assembly of claim 15, wherein hot gas path
temperatures and the plurality of compartments on the back surface
of the heat shield determine a number and location of the plurality
of impingement holes on the shell.
18. A combustor for a gas turbine engine, comprising: an inner
liner and an outer liner defining a combustion chamber; and a
bulkhead assembly at one end of the combustion chamber, the
bulkhead assembly having a heat shield mounted to and spaced apart
from a shell, the heat shield having a body having first and second
side edges, an inner edge, an outer edge, a back surface, a front
surface opposite the back surface, the back surface facing the
shell, and an opening in the body communicating through the front
and back surfaces, and a plurality of rails disposed on the back
surface, the plurality of rails dividing the back surface of the
body into a plurality of compartments for directing cooling air
flow, the plurality of rails including a first side rail disposed
on the first side edge, a second side rail disposed on the second
side edge, a radially inner rail extending along the inner edge,
the radially inner rail joining the first side rail and the second
side rail, a radially outer rail extending along the outer edge,
the radially outer rail joining the first side rail and the second
side rail, a circular rail concentrically disposed about the
opening, first and second mid-rails extending from opposite sides
of the circular rail, the first mid-rail joining the circular rail
and the first side rail, and the second mid-rail joining the
circular rail and the second side rail, and at least one radial
rail extending outwardly from the circular rail, the shell having a
plurality of impingement holes through which cooling air flow
passes and impinges on the back surface of the body of the heat
shield, each of the impingement holes located to achieve isothermal
temperatures on the heat shield, wherein the plurality of rails and
the plurality of compartments provide orientation of the cooling
air flow toward a plurality of effusion holes through the body of
the heat shield.
Description
FIELD OF THE DISCLOSURE
The present disclosure relates generally to gas turbine engines
and, more particularly, to combustors of a gas turbine engine.
BACKGROUND OF THE DISCLOSURE
Gas turbine engines typically include a compressor, a combustor,
and a turbine, with an annular flow path extending axially through
each. Initially, air flows through the compressor where it is
compressed or pressurized. The combustor then mixes and ignites the
compressed air with fuel, generating hot combustion gases. These
hot combustion gases are then directed by the combustor to the
turbine where power is extracted from the hot gases by causing
blades of the turbine to rotate.
The combustor is typically comprised of spaced apart inner and
outer liners, which define a combustion chamber. At the upstream
end of the combustion chamber is a bulkhead. The bulkhead includes
a plurality of openings to accommodate fuel nozzles, which project
into the forward end of the combustion chamber to supply fuel.
Due to the introduction and ignition of the combustion process, the
bulkhead is subject to extremely high temperatures. As a result,
damage to the bulkhead may occur from exposure to hot combustion
gases. Accordingly, there exists a need to provide the bulkhead
with effective cooling.
SUMMARY OF THE DISCLOSURE
According to one embodiment of the present disclosure, a heat
shield for a combustor is disclosed. The heat shield may comprise a
body having a back surface and an opposite front surface, wherein
an opening in the body communicates through the front and back
surfaces. The heat shield may further comprise at least one radial
rail disposed on the back surface and extending radially outward
from the opening for directing cooling air flow.
In a refinement, a plurality of effusion holes may extend from the
back surface to the front surface, the effusion holes providing
discharge of the cooling air flow from the back surface to the
front surface.
In a related refinement, the plurality of effusion holes may extend
either perpendicularly or at an angle from the back surface to the
front surface.
In another refinement, at least one oblong-shaped rib may be
disposed on the back surface.
In another refinement, a plurality of radial inner ribs may be
disposed on the back surface near an inner edge of the body.
In another refinement, a plurality of radial outer ribs may be
disposed on the back surface near an outer edge of the body.
In another refinement, on the back surface of the body, an inner
rail may disposed about an inner edge of the body, an outer rail
may be disposed about an outer edge of the body, a first side rail
may be disposed about a first side edge of the body, a second side
rail may be disposed about a second side edge of the body, a
circular rail may be concentrically disposed about the opening, and
a mid-rail laterally may extend from opposite sides of the circular
rail to the first and second side rails, the mid-rail dividing the
body into a radially outward half and a radially inward half with
respect to the combustor centerline.
In a related refinement, a first set of effusion holes may be
disposed between the inner rail and a plurality of radial inner
ribs, the inner rail and the plurality of radial inner ribs
directing the cooling air flow to the first set of effusion holes.
A second set of effusion holes may be disposed between the outer
rail and a plurality of radial outer ribs, the outer rail and the
plurality of radial outer ribs directing the cooling air flow to
the second set of effusion holes.
In a related refinement, a third set of effusion holes may surround
the circular rail, and the inner, outer, first side, second side,
circular, mid- and radial rails and radial inner and outer ribs may
direct the flow to the third set of effusion holes.
In a related refinement, the radial inner and outer ribs may
generally extend circumferentially with respect to the combustor
centerline and may be laterally oriented in a staggered arrangement
near the inner and outer edges, respectively.
In a related refinement, a staggered arrangement of the radial
inner and outer ribs may at least partially separate the inner and
outer edges from the rest of the body.
In another refinement, a plurality of pins may be disposed on the
back surface, and the pins spatially may be arranged in a diamond
formation.
In another refinement, a plurality of pins may be disposed on the
back surface, and the pins may be spatially arranged in a chevron
formation.
In yet another refinement, a plurality of raised trip strips may be
disposed on the back surface, and the plurality of raised trip
strips may be configured to further direct flow on the back
surface.
In a related refinement, the raised trip strips may be v-shaped or
chevrons.
According to another embodiment, a bulkhead assembly is disclosed.
The bulkhead assembly may comprise a heat shield mounted to and
spaced apart from a shell, the shell having a plurality of
impingement holes through which flow passes and impinges on the
heat shield. The heat shield may have a body having a back surface
and an opposite front surface, wherein an opening in the body
communicates through the front and back surfaces. The heat shield
may further have a plurality of radial rails disposed on the back
surface and extending radially outward from the opening, the radial
rails dividing the back surface of the body into a plurality of
compartments for directing cooling air flow. The heat shield may
further have a plurality of effusion holes in the body
communicating through the front and back surfaces, the effusion
holes providing discharge of the flow from the back surface to the
front surface.
In a refinement, each of the impingement holes through the shell
may be located to achieve isothermal temperatures on the heat
shield.
In another refinement, hot gas path temperatures and the
compartments on the back surface of the heat shield may determine a
number and location of impingement holes on the shell.
According to yet another embodiment, a combustor for a gas turbine
engine is disclosed. The combustor may comprise an inner liner and
an outer liner defining a combustion chamber, and a bulkhead
assembly at one end of the combustion chamber. The bulkhead
assembly may have a heat shield mounted to and spaced apart from a
shell. The heat shield may have a body having a back surface and an
opposite front surface, the back surface facing the shell, and
wherein an opening in the body communicates through the front and
back surfaces. The heat shield may further have a plurality of
radial rails disposed on the back surface and extending radially
outward from the opening, the radial rails dividing the back
surface of the body into a plurality of compartments for directing
cooling air flow. The shell may have a plurality of impingement
holes through which flow passes and impinges on the back surface of
the body of the heat shield, each of the impingement holes located
to achieve isothermal temperatures on the panels.
In a refinement, the radial rails and the compartments may provide
preferential orientation of the cooling air flow toward a plurality
of effusion holes through the body of the heat shield.
These and other aspects and features of the disclosure will become
more readily apparent upon reading the following detailed
description when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross-sectional view of a gas turbine engine
according to one embodiment of the present disclosure;
FIG. 2 is a cross-sectional view of part of a combustor of the gas
turbine engine of FIG. 1;
FIG. 3 is a perspective view of a front surface of a heat shield of
the combustor of FIG. 2;
FIG. 4 is a perspective view of a back surface of the heat shield
of FIG. 3;
FIG. 5 is a front view of a panel of the heat shield of FIG. 4;
FIG. 6 is a front view of the back surface of the panel of FIG.
5;
FIG. 7 is a front view of a back surface of a heat shield panel
with a plurality of pins arranged in a diamond configuration
according to another embodiment of the present disclosure;
FIG. 8 is a front view of a back surface of a heat shield panel
with a plurality of pins arranged in a chevron formation according
to another embodiment of the present disclosure;
FIG. 9 is a front view of a back surface of a heat shield panel
with a plurality of raised trips strips in a chevron formation
according to another embodiment of the present disclosure;
FIG. 10 is an exemplary flowchart outlining a method for designing
a bulkhead assembly for a combustor of a gas turbine engine
according to yet another embodiment of the present disclosure;
and
FIG. 11 is a front view of a back surface of a bulkhead heat shield
panel designed using the method outlined in the flowchart of FIG.
10.
While the present disclosure is susceptible to various
modifications and alternative constructions (i.e. may be a
manufacturing or repair technic), certain illustrative embodiments
thereof, will be shown and described below in detail. It should be
understood, however, that there is no intention to be limited to
the specific embodiments disclosed, but on the contrary, the
intention is to cover all modifications, alternative constructions,
and equivalents along within the spirit and scope of the present
disclosure.
DETAILED DESCRIPTION
Referring now to the drawings, and with specific reference to FIG.
1, in accordance with the teachings of the disclosure, an exemplary
gas turbine engine 110 is shown. The gas turbine engine 110 may
generally comprise a compressor section 112 where air is
pressurized, a combustor 2 which mixes and ignites the compressed
air with fuel generating hot combustion gases, a turbine section
114 for extracting power from the hot combustion gases, and an
annular flow path 116 extending axially through each. It will be
understood that the combustor 2 as disclosed herein is not limited
to the depicted embodiment of the gas turbine engine 110 but may be
applicable to other types of gas turbine engines.
Referring now to FIG. 2, an exemplary cross-sectional view of part
of a combustor 2 of the gas turbine engine 110 is shown. The
combustor 2 may comprise an inner liner 4 and an outer liner 6,
which define a combustion chamber 8. At an upstream end 10 of the
combustion chamber 8 may be a bulkhead assembly 12. The bulkhead
assembly may comprise a bulkhead heat shield 14 mounted to a
bulkhead shell 16. The heat shield 14 may be spaced apart from the
shell 16 such that there is a distance between the heat shield 14
and shell 16. As shown best in FIGS. 3 and 4, the heat shield 14
may be comprised of a plurality of panels 18 having a front surface
20 and a back surface 22 facing the shell 16. On the back surface
22 of the panel 18 may extend a plurality of studs 24 for mounting
of the panel 18 onto the shell 16 and for maintaining the distance
between the heat shield 14 and the shell 16. To provide cooling for
the heat shield 14, the shell 16 may have a plurality of
impingement holes through which air flow passes and impinges on the
back surface 22 of the heat shield 14. The impingement holes on the
shell 16 may be normal or angled to the heat shield 14.
Referring now to FIG. 5, each panel 18 of the heat shield 14 may
comprise a body 25 having a radially inner edge 26, a radially
outer edge 28, and two lateral edges 30 which abut
circumferentially adjacent heat shield panels. Each panel 18 may
also have a fuel nozzle opening 32 to accommodate a fuel nozzle and
a plurality of effusion holes 34 to provide discharge of the
impingement flow from the back surface 22 to the front surface 20
of the panel 18 and into the combustion chamber 8. For example, the
plurality of effusion holes 34 may include a first set 36 of
effusion holes 34 surrounding the radially inner edge 26, a second
set 38 of effusion holes 34 surrounding the radially outer edge 28,
and a third set 40 of effusion holes 34 surrounding the fuel nozzle
opening 32. The effusion holes 34 may extend perpendicularly from
the back surface 22 to the front surface 20 of the panel 18, or
they may extend at an angle from the back surface 22 to the front
surface 20 of the panel 18.
Turning now to FIG. 6, each panel 18 may further comprise an inner
rail 42 on or near the radially inner edge 26, an outer rail 44 on
or near the radially outer edge 28, and two side rails 46 on or
near the two lateral edges 30. A circular rail 48 may
concentrically align with or surround the fuel nozzle opening 32.
Extending laterally from opposite sides of the circular rail 48 (or
fuel nozzle opening 32) to the two side rails 46 (or lateral edges
30) may be a mid-rail 50, which divides the panel 18 into a
radially outward half 52 and a radially inward half 54 with respect
to the combustor centerline. To direct the impingement flow on the
back surface 22 of the panel 18, a plurality of radial rails 56 may
extend radially outward from the circular rail 48 (or fuel nozzle
opening 32), dividing each of the radially outward half 52 and
radially inward half 54 into a plurality of compartments 58. Due to
the mid-rail 50, radial rails 56 and formation of compartments 58,
the impingement flow may be preferentially oriented toward the
effusion holes 34. More specifically, the radial rails 56 may be
placed circumferentially to enclose the flow within each
compartment 58 and accelerate the flow toward the effusion holes 34
within a converging passage. Although shown as having six radial
rails 56 and eight compartments 58 in FIG. 6, it will be understood
that the number of rails 56 and compartments 58 on the panel 18 are
for exemplary purposes only, and that any number of rails 56 and
compartments 58 may be employed on the panel 18 without departing
from the scope of this disclosure.
The mid-rails 50, like the radial rails 56 generally extend in a
radial direction and may project from or attach to the circular
rail 48. Both the mid-rails 50 and the radial rails 56, together
may define at least some of the compartments 58. Unlike the radial
rails 56 which terminate at a distal end, the mid-rails 50
terminate radially outward at the respective side rails 46 and thus
attach to the side rails 46.
In addition, each panel 18 may have a plurality of oblong-shaped
protrusions or ribs 60 laterally oriented in a staggered
arrangement. The ribs 60 may in part define the radial compartments
58. Generally extending circumferentially with respect to the
combustor centerline, the ribs 60 may be located near the radially
inner and outer edges 26, 28 to generally or at least partially
separate the inner and outer edges 26, 28 from the rest of the
panel 18 thus enhancing cooling generally at the edges 26, 28.
Providing flow resistance to the radially inner and outer edges 26,
28, the staggered arrangement of the ribs 60 may also allow partial
flow around opposite ends 62 of each rib 60. Although shown and
described as laterally oriented in a staggered arrangement, it will
be understood that other orientations and arrangements of the ribs
60 may be used without departing from the scope of the invention.
For example, in another embodiment, the ribs 60 may be oriented in
a zig-zag formation (not shown), while still segregating the inner
and outer edges 26, 28 from the rest of the panel 18.
Furthermore, the first set 36 of effusion holes 34 may be
distributed between the inner rail 42 and a plurality of radial
inner ribs 64, and the second set 38 of effusion holes 34 may be
distributed between the outer rail 44 and a plurality of radial
outer ribs 66. This results in the radial inner ribs 64 and the
inner rail 42 directing flow toward the first set 36 of effusion
holes 34; and the radial outer ribs 66 and the outer rail 44
directing flow toward the second set 38 of effusion holes 34. At
the same time, the radial inner and outer ribs 64, 66 may partially
block the impingement flow away from the inner and outer rails 42,
44, (or radially inner and outer edges 26, 28) respectively,
thereby directing the flow within the compartments 58. As a result
of a network of rails 42, 44, 46, 48, 50, 56, compartments 58, and
ribs 60, the flow is directed and accelerated in a converging
passage toward the third set 40 of effusion holes 34 surrounding
the circular rail 48.
Within the compartments 58, a plurality of pins 68 may extend from
the back surface 22 of the panel 18 to increase a surface area of
heat transfer, turbulate and direct the flow. As shown in FIG. 7,
the pins 68 may be spatially arranged in a diamond configuration,
such as that outlined by diamond formation 70, to enhance heat
transfer and further direct the flow. As shown in FIG. 8, the pins
68 may be spatially arranged in a chevron formation 72, or two
v-shaped rows of pins 68 in each compartment 58. According to
another embodiment and as shown in FIG. 9, a plurality of raised
trip strips 74 may extend from the back surface 22 of the panel 18
within each compartment 58. The raised trip strips 74 may be in a
chevron formation, or v-shaped. The chevron formation or v-shaped
configuration of pins 68 and trip strips 74 further enhance
preferential orientation of the flow on the back surface 22 of the
panel 18 by directing the flow to the adjacent radial rails 56 or
mid-rail 50, which then guide the flow downstream toward the third
set 40 of effusion holes 34 for discharge into the combustion
chamber 8. Other formations and arrangements of the pins 68 and
raised trip strips 74, or combinations thereof, are certainly
possible.
Turning now to FIG. 10, an exemplary flowchart outlining a method
for designing a bulkhead assembly for a gas turbine engine
combustor is shown, according to yet another embodiment of the
present disclosure. Starting at step 80, the heat shield may be
provided with a backside cooling configuration. For example, each
panel of the heatshield may be provided with a body having a back
surface facing the shell, an inner edge, an outer edge, a first
side edge, a second side edge, and a fuel nozzle opening, an inner
rail disposed about the inner edge, an outer rail disposed about
the outer edge, a first side rail disposed about the first side
edge, a second side rail disposed about the second side edge, a
circular rail concentrically disposed about the fuel nozzle
opening, and a mid-rail laterally extending from opposite sides of
the circular rail to the first and second side rails, the mid-rail
dividing the panel into an upper half and a lower half. Each panel
may further be provided with a plurality of radial rails extending
radially outward from the circular rail and dividing each of the
upper and lower halves into a plurality of compartments, a
plurality of pin fins provided within each of the compartments, and
a plurality of effusion holes extending from the back surface of
the panel to a front surface of the panel. The effusion holes may
provide discharge of the flow from the back surface of the panel
into a combustion chamber.
Next at step 82, hot gas path temperatures on the heat shield may
be observed. At next step 84, an arrangement, number and location
of the impingement holes on the shell may be determined based on
the observation of hot gas path temperatures on the heat shield.
The impingement hole arrangement on the shell may be designed to
achieve isothermal temperatures on the panels. For example, after
observing hot gas path temperatures and determining a location of
hot spots on the panels, the number and location of impingement
holes on the shell may be tailored to provide more cooling to the
hot spots on the panels with consideration of the compartments on
the back surface of the panels. At the last step 86, the shell may
be provided with impingement holes at the determined locations from
the previous step.
As shown in FIG. 11, a plurality of targets 90 represent the
location of impingement holes and impinging air flow from the shell
projected onto the back surface 22 of the panel 18. Once the flow
impinges onto the back surface 22 of the panel 18, the network of
rails 42, 44, 46, 48, 50, 56, compartments 58, 100, ribs 60, and
pins 68 provide preferential orientation of the flow toward the
effusion holes 34. Specifically, the radial inner ribs 64 and the
inner rail 42 direct flow toward the first set 36 of effusion holes
34, as depicted by arrows 92. As depicted by arrows 94, the radial
outer ribs 66 and the outer rail 44 direct flow toward the second
set 38 of effusion holes 34. As depicted by arrows 96, the radial
inner and outer ribs 64, 66, radial rails 56, inner rail 42, outer
rail 44, side rails 46, circular rail 48, mid-rail 50, and pins 68
direct flow toward the third set 40 of effusion holes 34.
Furthermore, if for example, a hot spot 98 on the panel 18 is
determined to be in compartment 100, increased impingement flow may
be provided to compartment 100 by providing an increased number of
impingement holes through the shell in the location on the shell
that will project impingement flow to the targeted hot spot 98 on
compartment 100 of the panel 18. Directly tailoring the number and
location of impingement holes on the shell to the hot gas path
temperatures and compartments on the panels of the heat shield
varies the amount of cooling flow within each compartment. As a
result, hot spots on the heat shield can be accounted for and
isothermal temperatures or an improved temperature distribution can
be achieved.
It will be understood that the arrangement, number, location, and
placement of impingement hole targets 90, radial rails 56,
compartments 58, 100, effusion holes 34, ribs 60, and pins 68 shown
in FIG. 11 are for exemplary purposes only and that any type of
variation of these components may be made without departing from
the scope of this disclosure. For example, the number and placement
of radial rails 56 and compartments 58, 100 may vary due to the hot
gas path temperatures and location of hot spots. In addition, the
number of effusion holes in the heat shield may vary with respect
to the number of impingement holes in the shell (or vice versa) in
order to customize the pressure drop across each of the heat shield
and the shell and optimize the pressure drop across the bulkhead
assembly.
INDUSTRIAL APPLICABILITY
From the foregoing, it can be seen that the teachings of this
disclosure can find industrial application in any number of
different situations, including but not limited to, gas turbine
engines. Such engines may be used, for example, on aircraft for
generating thrust, or in land, marine, or aircraft applications for
generating power.
The disclosure described provides an effective cooling
configuration for the bulkhead assembly of a gas turbine engine
combustor. By compartmentalizing the back surface of the panels,
the impingement flow is provided with preferential orientation,
thereby increasing the cooling effectiveness while utilizing a
minimal cooling flow budget. Moreover, by tailoring the location
and number of impingement holes on the shell, isothermal
temperatures on the panels can be achieved. In addition, the ribs
and pin arrangements disclosed herein enhance the ability to direct
flow and transfer heat on the panels. As a result of the numerous
cooling features disclosed herein, the durability and part life of
the bulkhead assembly is improved.
While the foregoing detailed description has been given and
provided with respect to certain specific embodiments, it is to be
understood that the scope of the disclosure should not be limited
to such embodiments, but that the same are provided simply for
enablement and best mode purposes. The breadth and spirit of the
present disclosure is broader than the embodiments specifically
disclosed and encompassed within the claims appended hereto.
* * * * *